HomeGenetics UnderstandingInheritanceAre chromosomal disorders inherited?
Back to Inheritance
Are chromosomal disorders inherited?
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Inheritance

Are Chromosomal Disorders Inherited?

While some chromosomal abnormalities can be passed down through generations, most are the result of random events during the formation of reproductive cells or early fetal development.

Overview of Inheritance

Although it is possible to inherit some types of chromosomal abnormalities, most chromosomal disorders (such as Down syndrome and Turner syndrome) are not passed from one generation to the next.

Causes of Chromosomal Disorders

Changes in Chromosome Number

Some chromosomal conditions are caused by changes in the number of chromosomes. These changes are not inherited but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in reproductive cells with an abnormal number of chromosomes.

  • A reproductive cell may accidentally gain or lose one copy of a chromosome.
  • If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra or missing chromosome in each of the body’s cells.

Changes in Chromosome Structure

Changes in chromosome structure can also cause chromosomal disorders. The inheritance of these changes can be complex:

  • Some changes in chromosome structure can be inherited.
  • Others occur as random accidents during the formation of reproductive cells or in early fetal development.

Because the inheritance of these changes can be complex, people concerned about this type of chromosomal abnormality may want to talk with a genetics professional.

Somatic Cell Changes

Some cancer cells also have changes in the number or structure of their chromosomes. Because these changes occur in somatic cells (cells other than eggs and sperm), they cannot be passed from one generation to the next.

Frequently Asked Questions

You can have a karyotype analysis performed on a blood sample. If a structural rearrangement is detected, further testing such as fluorescence in situ hybridization (FISH) or array CGH can pinpoint the exact breakpoints. Once identified, options like preimplantation genetic testing (PGT‑M) or detailed prenatal screening can be offered.
In many families, the apparent “multiple affected members” are due to a parental balanced translocation or mosaicism that increases the chance of an abnormal gamete. In other cases, unrelated de‑novo events can occur in different family members, especially if the parents are older. A thorough genetic evaluation of each affected individual can clarify whether a shared inherited abnormality exists.
Most cases of Down syndrome arise from a random nondisjunction event during egg or sperm formation, so they are not inherited. However, a small number of families carry a balanced translocation that can lead to an increased risk of having a child with Down syndrome. If you or your partner have a known chromosomal abnormality, a genetic counselor can calculate your specific recurrence risk and discuss options such as prenatal testing or preimplantation genetic diagnosis.
The risk depends on the type of chromosomal change. For example, a parent with a balanced translocation has about a 10‑15% chance of having an affected child, while a de‑novo trisomy has a very low recurrence risk. A karyotype of both parents and, if possible, a detailed family history are needed to estimate the exact risk.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

kontakt@hittavard.se

Ⓒ 2024. Alla rättigheter förbehålls av juxt ab

Sök
Om ossVillkor och policyVanliga frågorKontakta oss